1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed 8 * to Berkeley by John Heidemann of the UCLA Ficus project. 9 * 10 * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)vfs_init.c 8.3 (Berkeley) 1/4/94 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/fnv_hash.h> 45 #include <sys/jail.h> 46 #include <sys/kernel.h> 47 #include <sys/linker.h> 48 #include <sys/mount.h> 49 #include <sys/proc.h> 50 #include <sys/sx.h> 51 #include <sys/syscallsubr.h> 52 #include <sys/sysctl.h> 53 #include <sys/vnode.h> 54 #include <sys/malloc.h> 55 56 static int vfs_register(struct vfsconf *); 57 static int vfs_unregister(struct vfsconf *); 58 59 MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes"); 60 61 /* 62 * The highest defined VFS number. 63 */ 64 int maxvfsconf = VFS_GENERIC + 1; 65 66 /* 67 * Single-linked list of configured VFSes. 68 * New entries are added/deleted by vfs_register()/vfs_unregister() 69 */ 70 struct vfsconfhead vfsconf = TAILQ_HEAD_INITIALIZER(vfsconf); 71 struct sx vfsconf_sx; 72 SX_SYSINIT(vfsconf, &vfsconf_sx, "vfsconf"); 73 74 /* 75 * Loader.conf variable vfs.typenumhash enables setting vfc_typenum using a hash 76 * calculation on vfc_name, so that it doesn't change when file systems are 77 * loaded in a different order. This will avoid the NFS server file handles from 78 * changing for file systems that use vfc_typenum in their fsid. 79 */ 80 static int vfs_typenumhash = 1; 81 SYSCTL_INT(_vfs, OID_AUTO, typenumhash, CTLFLAG_RDTUN, &vfs_typenumhash, 0, 82 "Set vfc_typenum using a hash calculation on vfc_name, so that it does not" 83 "change when file systems are loaded in a different order."); 84 85 /* 86 * A Zen vnode attribute structure. 87 * 88 * Initialized when the first filesystem registers by vfs_register(). 89 */ 90 struct vattr va_null; 91 92 /* 93 * vfs_init.c 94 * 95 * Allocate and fill in operations vectors. 96 * 97 * An undocumented feature of this approach to defining operations is that 98 * there can be multiple entries in vfs_opv_descs for the same operations 99 * vector. This allows third parties to extend the set of operations 100 * supported by another layer in a binary compatibile way. For example, 101 * assume that NFS needed to be modified to support Ficus. NFS has an entry 102 * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by 103 * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions) 104 * listing those new operations Ficus adds to NFS, all without modifying the 105 * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but 106 * that is a(whole)nother story.) This is a feature. 107 */ 108 109 /* 110 * Routines having to do with the management of the vnode table. 111 */ 112 113 static struct vfsconf * 114 vfs_byname_locked(const char *name) 115 { 116 struct vfsconf *vfsp; 117 118 sx_assert(&vfsconf_sx, SA_LOCKED); 119 if (!strcmp(name, "ffs")) 120 name = "ufs"; 121 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) { 122 if (!strcmp(name, vfsp->vfc_name)) 123 return (vfsp); 124 } 125 return (NULL); 126 } 127 128 struct vfsconf * 129 vfs_byname(const char *name) 130 { 131 struct vfsconf *vfsp; 132 133 vfsconf_slock(); 134 vfsp = vfs_byname_locked(name); 135 vfsconf_sunlock(); 136 return (vfsp); 137 } 138 139 struct vfsconf * 140 vfs_byname_kld(const char *fstype, struct thread *td, int *error) 141 { 142 struct vfsconf *vfsp; 143 int fileid, loaded; 144 145 vfsp = vfs_byname(fstype); 146 if (vfsp != NULL) 147 return (vfsp); 148 149 /* Try to load the respective module. */ 150 *error = kern_kldload(td, fstype, &fileid); 151 loaded = (*error == 0); 152 if (*error == EEXIST) 153 *error = 0; 154 if (*error) 155 return (NULL); 156 157 /* Look up again to see if the VFS was loaded. */ 158 vfsp = vfs_byname(fstype); 159 if (vfsp == NULL) { 160 if (loaded) 161 (void)kern_kldunload(td, fileid, LINKER_UNLOAD_FORCE); 162 *error = ENODEV; 163 return (NULL); 164 } 165 return (vfsp); 166 } 167 168 169 /* Register a new filesystem type in the global table */ 170 static int 171 vfs_register(struct vfsconf *vfc) 172 { 173 struct sysctl_oid *oidp; 174 struct vfsops *vfsops; 175 static int once; 176 struct vfsconf *tvfc; 177 uint32_t hashval; 178 int secondpass; 179 180 if (!once) { 181 vattr_null(&va_null); 182 once = 1; 183 } 184 185 if (vfc->vfc_version != VFS_VERSION) { 186 printf("ERROR: filesystem %s, unsupported ABI version %x\n", 187 vfc->vfc_name, vfc->vfc_version); 188 return (EINVAL); 189 } 190 vfsconf_lock(); 191 if (vfs_byname_locked(vfc->vfc_name) != NULL) { 192 vfsconf_unlock(); 193 return (EEXIST); 194 } 195 196 if (vfs_typenumhash != 0) { 197 /* 198 * Calculate a hash on vfc_name to use for vfc_typenum. Unless 199 * all of 1<->255 are assigned, it is limited to 8bits since 200 * that is what ZFS uses from vfc_typenum and is also the 201 * preferred range for vfs_getnewfsid(). 202 */ 203 hashval = fnv_32_str(vfc->vfc_name, FNV1_32_INIT); 204 hashval &= 0xff; 205 secondpass = 0; 206 do { 207 /* Look for and fix any collision. */ 208 TAILQ_FOREACH(tvfc, &vfsconf, vfc_list) { 209 if (hashval == tvfc->vfc_typenum) { 210 if (hashval == 255 && secondpass == 0) { 211 hashval = 1; 212 secondpass = 1; 213 } else 214 hashval++; 215 break; 216 } 217 } 218 } while (tvfc != NULL); 219 vfc->vfc_typenum = hashval; 220 if (vfc->vfc_typenum >= maxvfsconf) 221 maxvfsconf = vfc->vfc_typenum + 1; 222 } else 223 vfc->vfc_typenum = maxvfsconf++; 224 TAILQ_INSERT_TAIL(&vfsconf, vfc, vfc_list); 225 226 /* 227 * Initialise unused ``struct vfsops'' fields, to use 228 * the vfs_std*() functions. Note, we need the mount 229 * and unmount operations, at the least. The check 230 * for vfsops available is just a debugging aid. 231 */ 232 KASSERT(vfc->vfc_vfsops != NULL, 233 ("Filesystem %s has no vfsops", vfc->vfc_name)); 234 /* 235 * Check the mount and unmount operations. 236 */ 237 vfsops = vfc->vfc_vfsops; 238 KASSERT(vfsops->vfs_mount != NULL, 239 ("Filesystem %s has no mount op", vfc->vfc_name)); 240 KASSERT(vfsops->vfs_unmount != NULL, 241 ("Filesystem %s has no unmount op", vfc->vfc_name)); 242 243 if (vfsops->vfs_root == NULL) 244 /* return file system's root vnode */ 245 vfsops->vfs_root = vfs_stdroot; 246 if (vfsops->vfs_quotactl == NULL) 247 /* quota control */ 248 vfsops->vfs_quotactl = vfs_stdquotactl; 249 if (vfsops->vfs_statfs == NULL) 250 /* return file system's status */ 251 vfsops->vfs_statfs = vfs_stdstatfs; 252 if (vfsops->vfs_sync == NULL) 253 /* 254 * flush unwritten data (nosync) 255 * file systems can use vfs_stdsync 256 * explicitly by setting it in the 257 * vfsop vector. 258 */ 259 vfsops->vfs_sync = vfs_stdnosync; 260 if (vfsops->vfs_vget == NULL) 261 /* convert an inode number to a vnode */ 262 vfsops->vfs_vget = vfs_stdvget; 263 if (vfsops->vfs_fhtovp == NULL) 264 /* turn an NFS file handle into a vnode */ 265 vfsops->vfs_fhtovp = vfs_stdfhtovp; 266 if (vfsops->vfs_checkexp == NULL) 267 /* check if file system is exported */ 268 vfsops->vfs_checkexp = vfs_stdcheckexp; 269 if (vfsops->vfs_init == NULL) 270 /* file system specific initialisation */ 271 vfsops->vfs_init = vfs_stdinit; 272 if (vfsops->vfs_uninit == NULL) 273 /* file system specific uninitialisation */ 274 vfsops->vfs_uninit = vfs_stduninit; 275 if (vfsops->vfs_extattrctl == NULL) 276 /* extended attribute control */ 277 vfsops->vfs_extattrctl = vfs_stdextattrctl; 278 if (vfsops->vfs_sysctl == NULL) 279 vfsops->vfs_sysctl = vfs_stdsysctl; 280 281 if (vfc->vfc_flags & VFCF_JAIL) 282 prison_add_vfs(vfc); 283 284 /* 285 * Call init function for this VFS... 286 */ 287 (*(vfc->vfc_vfsops->vfs_init))(vfc); 288 vfsconf_unlock(); 289 290 /* 291 * If this filesystem has a sysctl node under vfs 292 * (i.e. vfs.xxfs), then change the oid number of that node to 293 * match the filesystem's type number. This allows user code 294 * which uses the type number to read sysctl variables defined 295 * by the filesystem to continue working. Since the oids are 296 * in a sorted list, we need to make sure the order is 297 * preserved by re-registering the oid after modifying its 298 * number. 299 */ 300 sysctl_wlock(); 301 SLIST_FOREACH(oidp, SYSCTL_CHILDREN(&sysctl___vfs), oid_link) { 302 if (strcmp(oidp->oid_name, vfc->vfc_name) == 0) { 303 sysctl_unregister_oid(oidp); 304 oidp->oid_number = vfc->vfc_typenum; 305 sysctl_register_oid(oidp); 306 break; 307 } 308 } 309 sysctl_wunlock(); 310 311 return (0); 312 } 313 314 315 /* Remove registration of a filesystem type */ 316 static int 317 vfs_unregister(struct vfsconf *vfc) 318 { 319 struct vfsconf *vfsp; 320 int error, maxtypenum; 321 322 vfsconf_lock(); 323 vfsp = vfs_byname_locked(vfc->vfc_name); 324 if (vfsp == NULL) { 325 vfsconf_unlock(); 326 return (EINVAL); 327 } 328 if (vfsp->vfc_refcount != 0) { 329 vfsconf_unlock(); 330 return (EBUSY); 331 } 332 if (vfc->vfc_vfsops->vfs_uninit != NULL) { 333 error = (*vfc->vfc_vfsops->vfs_uninit)(vfsp); 334 if (error != 0) { 335 vfsconf_unlock(); 336 return (error); 337 } 338 } 339 TAILQ_REMOVE(&vfsconf, vfsp, vfc_list); 340 maxtypenum = VFS_GENERIC; 341 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) 342 if (maxtypenum < vfsp->vfc_typenum) 343 maxtypenum = vfsp->vfc_typenum; 344 maxvfsconf = maxtypenum + 1; 345 vfsconf_unlock(); 346 return (0); 347 } 348 349 /* 350 * Standard kernel module handling code for filesystem modules. 351 * Referenced from VFS_SET(). 352 */ 353 int 354 vfs_modevent(module_t mod, int type, void *data) 355 { 356 struct vfsconf *vfc; 357 int error = 0; 358 359 vfc = (struct vfsconf *)data; 360 361 switch (type) { 362 case MOD_LOAD: 363 if (vfc) 364 error = vfs_register(vfc); 365 break; 366 367 case MOD_UNLOAD: 368 if (vfc) 369 error = vfs_unregister(vfc); 370 break; 371 default: 372 error = EOPNOTSUPP; 373 break; 374 } 375 return (error); 376 } 377